(EN) Lakshman Achuthan e Anirvan Banerji, The risk of redefining recession, in CNN Money, 5 maggio 2008.
«The idea originated in a 1974 New York Times article by Julius Shiskin, who provided a laundry list of recession-spotting rules of thumb, including two down quarters of GDP. Over the years the rest of his rules somehow dropped away, leaving behind only "two down quarters of GDP."»
